Alex Tolley

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I suppose he could have said "I buy my wife lots of things". To which you could have replied: "But how did you determine the price for each thing she does for you, besides the sex?". MBAs with brains understand...

I also find I read less SF these days, but not because of problems of worldbuilding. Douglas Adams once said that he had given up litfic because there was nothing new to read about. I read SF mostly to be...

In the West, primarily Anglo-Speaking West, economics and finance (especially) focussed on entities maximiming gains. For firms this meant sharegholders, while elsewhere other stakeholders were also part of decision-making. AI in the US was often focussed on "winning", whether beating...

paperclip maximizer = replicator So we have had replicators since life began. The result has been a flowering of life, particularly of metazoa. Ai today and the near future is primarily software, so the nearest replicator analogy is memes. We've...

There's nowhere in the Solar System we really want to go anyway You are making teh assumption that humans must be colonizing the solar system for there to be any need for infrastructure and transport. There can be an entirely...

You are right. The engines represent the bulk of the dry mass as they are increased in number to increase thrust. At 25 kg each, one cannot scale up the vehicle fast enough to make sense. (The solar array mass...

Indium ion micro thrusters. Yes, Isp of 10,000+s was measured paper: http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1997ESASP.398..267R&db_key=AST&page_ind=0&plate_select=NO&data_type=GIF&type=SCREEN_GIF&classic=YES Nasa news report on printed approach: https://microdevices.jpl.nasa.gov/capabilities/advanced-microfabrication-technologies/microfluidic-electrospray-propulsion.php These look more suitable for tiny satellites and position keeping, but they may well offer scale-up opportunities....

I assumed no mass for the engines, just the mass of the arrays with an assumed power density that could be raised 10x. MIT has demonstrated super-thin film arrays in the lab at 6W/g, I think it is not unreasonable...

Storage is easy, we know how to do that. You don't run hoses, but rather fill a smaller container truck, drive over to the ship and pump into the tanks, just as we manage jet fuel with aircraft at airports,...

Before writing off high-thrust ion drives, buy increasing the power to run multiple engines you can get much more thrust and short travel times. The problem is the power supply. Those nice solar arrays have too low a power density....

Good question. It all depends on the interpretation of the meaning of "...a resident "within the United States" for 14 years...". The territorial status of PR makes that requirement a bit ambiguous. OTOH, the GOP were willing to have Arnie...

Obviously making LOX won't be a simple matter of waving a magician's wand, but try not to be so dismissive of what can be done. The Moon is cold enough to allow extremely low temperatures to be achieved. Liquification might...

I should have watched his IAC presentation first. Looks like he does want to land his BFR on the Moon quite soon. Fuel will be launched from Earth rather than manufactured, although the LOX could be made on the Moon....

That would be the equivalent of landing the whole stack which makes no sense to me. Musk may however, be thinking along those lines in the future. The BFR reaches orbit, refuels, then descends and ascends at the Moon. Refuels...

Was it Clarke who said that the problem with ballistic flight was that the toilet was out of reach for 1/2 the time, and unusable for the other half. There really will need to be a last call for the...

Theoretically, SpaceX doesn't need a dedicated LM as the capsule can use rocket propulsion to land. With a delta v of less than 2.5 km/s for descent the fuel is not much more than the capsule's own mass. With refueling...

is this also going to destabilize the secondary insurance markets? I don't think so. Insurance and reinsurance is global and there is a lot of capital to draw on. Insurers will take a hit but not a bad one. I...

Because of the small mass of red dwarfs, the planets in the NZ are close in. That means that most are tidally locked. Which means that they probably do not have protective magnetic fields. While abundant, you are probably aware...

Back in teh 1970s when energy was getting expensive and buildings were mostly uninsulated, there were a host of simple, inexpensive solutions to reduce heat loss. You mentioned one. Getting hold of books from this era might be worth doing...

The main issue with EVs has been "range anxiety". And when you need recharging, how do you do it? "fast recharges" are possible, but clearly are still much slower than a gas station fill up. Removing the battery and replacing...

"decarbonize quickly, plant lots of trees, paint cities and roads white, implement robust and flexible farming techniques and wait 500 years to see if we survive." As Frank would probably say, we don't have 500 years, at least not...

When can I start claiming carbon credits for planting trees in my backyard? Presumably, this could be turned into a farm project with harvesting and sale to a government wood sequestration center. What about all that green waste? If it...

A good scam will be ocean fertilization for carbon credits. Cost is low, the CO2 uptake, in the short term, measurable. But because the algae don't sink and sequestrate the carbon, it is released again. I can also imagine putting...

California has a program to install solar panels on low-income houses for free. The kit cost is estimated to be $20-30k plus labor. For older homes, what should be done is add wall insulation as well as double-paned windows, but...

Comment Threads

which is a range of over 7:1. There's no rear gear that will provide that, and such motors do not support front gears Here in the advanced nation of Australia we have access to bleeding-edge technology from the 1990's such as the Sunstar and Stoke Monkey. This page from the US has a useful list of mid drive units and although many shown aren't road legal in AU/EU they generally come in variants that are. What's notable about many of those pictures is that they're apparently unaware of your requirement that they not support multiple chainrings, so they can be...

Quick check -- right now at 20180221 21:00 we're consuminging 42GW of electricity made up from... From http://www.gridwatch.templar.co.uk/ no? A most useful resource (I assume it's sort of right/reliable) and it would be nice to see similar from other countries and regions....

In practice I've been considering the exact opposite, a 200W motor geared to boost at 25-50kph because in Australia we have a split system, 200W with no speed limit or 250W limited to 25kph. One sneaky option that might be legal is dual motors and a single controller, because it's the system that's limited to 250W. I haven't checked that, but it would trade an extra 3kg for the second motor for a much simpler mechanical setup. I haven't bothered with the speed limit systems because those irritate me to the point where I only use them when I'm injured...

"There is an increasing belief among the people who analyse such things that those features have increased danger as much as they have reduced it. Because of those, people now driver faster, further, and often closer to the edge. " If you have links, I'd appreciate them. IIRC, Peltzman's original paper wasn't so good. It's pretty much a fundamental finding of cognitive psych that people s*ck at estimating small probabilities....

Don't try to predict the future. A) your wishes will make you stupid. Emotion destroys the capacity for rational thought; rationalizing thought takes over. The more IQ and information you have, the worse you will do, because you'll be better at convincing yourself of what you want to believe. (This applies to both utopian and dystopian visions of the future.) B) It would be inherently impossible anyway. There is too much information and you can't tell what part of it is significant or how it interacts. Eg., try to imagine a Roman deciding in 0 CE that the future would...